Demulsification of hydraulic oils using group ii metal sulfonates and hydroxylic combinations

ABSTRACT

EMULSIBILITY OF OILS HAVING MATERIAL CONTACT WITH WATER, E.G., HYDRAULIC OILS, IS SIGNIFICANTLY REDUCED BY THE ADDITION OF ALKANOLS OR DIOLS IN COMBINATION WITH A GROUP II METAL SULFONATE.

United States Patent DEMULSIFICATION 0F HYDRAULIC OILS USING GROUP H METAL SULFONATES AND HYDROX- YLIC COMBINATIONS James H. Walker, Pinole, Califi, assignor to Chevron Research Company, San Francisco, Calif. No Drawing. Filed Sept. 16, 1968, Ser. No. 762,334 Int. Cl. C10m 1/48 U.S. Cl. 25232.7 7 Claims ABSTRACT OF THE DISCLOSURE Emulsibility of oils having material contact with water, e.g., hydraulic oils, is significantly reduced by the addition of alkanols or diols in combination with a Group II metal sulfonate.

BACKGROUND OF THE INVENTION Field of the invention Highly paraffinic oils containing zinc organic phosphate salts find use as hydraulic fluids and turbine oils. It is frequently found that when these oils come in contact with water, serious emulsification problems occur. In order to have satisfactory lubricating oils of the above type, it is essential that the oil and water phase separate rapidly and there be little, if any, residual cuff. Not only must there be a satisfactory separation, but little, if any, water should be retained in the oil phase.

SUMMARY OF THE INVENTION Small amounts of alkanols or diols in combination with Group II metal sulfonates are added to paraffinic oils containing zinc organic phosphate salts to reduce emulsibility. The combination of the Group II metal sulfonates and the alcohols is found greatly to accelerate the separation of the oil and water phase and to minimize significantly the retention of water in the oil phase.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Lubricating oil compositions are provided, wherein the base oil has less than about 30 percent aromatic content (ndM analysisrefractive index, density, molecular weight), from about 0.1 to 2 weight percent of a zinc organic phosphate salt, and from 0.01 to 0.2 weight percent of the combination of Group II metal sulfonate; particularly, barium and zinc, and hydroxylic compound (monoor di) in a weight ratio of 15:1.

The hydroxylic compounds which find use as demulsifiers have one to two hydroxyl groups bonded to aliphatic carbon atoms, from to 12 carbon atoms and usually free of unsaturation, both aliphatic and aromatic.

Illustrative alcohols include 4-methyl-2-pentanol, octanol, nonanol, decanol, cyclohexanol, hexylene glycol, octylene glycol, decylene glycol, dodecanol, etc.

The preferred alkanols are those of from 5 to 8 carbon atoms, particularly branched chain alkanols.

The sulfonates which find use are Group II metal sulfonates, usually those of Group II metals of atomic number in the range of 30-5 6, and particularly the barium and zinc sulfonates. The sulfonates may be a variety of oil soluble metal sulfonates, particularly, alkylated aromatic sulfonates. The alkyl groups will generally be of from 8 to 30 carbon atoms, there being from one to two 'ice alkyl groups per aromatic ring, the total number of aliphatic carbon atoms being usually at least 8, preferably at least 10 and generally not exceeding 30. The aromatic ring will generally be of from 6 to 12 carbon atoms, more usually of from 6 to 10 carbon atoms.

Illustrative sulfonates are the mahogany sulfonates, dinonyl benzene sulfonate, dinonyl naphthalene sulfonate, hexyl octadecyl benzene sulfonate, octadecyl benzene sulfonate, ditetradecyl benzene sulfonate, etc.

The zinc organic phosphorodithioate salt is a commonly used additive in hydraulic and turbine fluids. It provides antiwear and antioxidant activity. Such zinc salts are well known in the art. See US. Pat. Nos. 2,680,123, 2,689,220, 2,717,241, and 2,734,864.

These salts are zinc 0,0-dihydrocarbyl phosphorodithioates wherein the hydrocarbyl is of from 4 to 30 carbon atoms and substantially free of aliphatic unsaturation. (By hydrocarbyl is intended an organic radical composed solely of carbon and hydrogen.) For the most part, the hydrocarbyl groups are alkyl groups or alkaryl groups, the alkyl groups finding particular use in the subject invention. The alkyl groups will generally be of from 4 to 12 carbon atoms, more usually of from 4 to 8 carbon atoms. The 2 alkyl groups may be the same or different, and if different, differing in carbon content from about 1 to 3 carbon atoms.

The demulsifying composition which is used will have from 1 to 5 parts of the alkanol or alkanediol to about 1 part of the zinc sulfonate, preferably 2 to 4 parts of the alkanol or diol per part of zinc sulfonate. This composition will be used in concentrations of from 0.01 to about 0.2 weight percent based on the total composition, preferably from about 0.03 to about 0.1 weight percent.

The zinc organic phosphorodithioate salt will be present in at least 0.1 Weight percent and usually not greater than 2 weight percent, more usually of from about 0.5 to 1.5 weight percent of the total composition.

The base oil which finds use will have less than about 30 percent aromatic carbon atoms based on ndM analysis. Usually, there will be at least about 50 percent paraflinic carbon atoms based on ndM analysis. The initial boiling point generally will be above 500 F., usually above 600 F. and the final boiling temperature, usually less than about 1,300 F., more usually less than about 1,200 F. Various oils which find use include neutral oils, pale oils, and spray oils which may be clay treated, acid treated, etc.

Various other additives are normally included in the compounded oil. These additives include antioxidants, e.g., 2,6-di-tert butyl para-cresol, methylene bis(4,4-di[2,6-di (tert.-butyl) phenol] etc., extreme pressure agents, such as dibenzyl disulfide, viscosity index improvers, foam inhibitors, and rust inhibitors, e.g., tetrapropenyl succinic acid. These additives, except for the foam inhibitor, will generally be present in from about 0.05 to 1 weight percent, more usually about 0.05 to 0.5 weight percent. The foam inhibitor will generally be present in from about 0.001 to 0.01 weight percent. The total amount of these other additives will ordinarily be in the range of about 0.5 to 3.0 weight percent.

In order to demonstrate the effectiveness of the compositions of this invention, a number of compositions were prepared and their water tolerance determined according to the ASTM D1401 emulsion test. The following table indicates the composition employed and the volume of the phases at a designated time after the composition had been stirred wtih water.

1 A 4-mcthyl-2-pentanol; B=hexylcne glycol.

2 C=Zinc dinonyl naphthalene sulionate; D=Ba dialkylbenzene sul- Ionate (alkyl from 5 to 0 and 18 to 20 carbon atoms).

3 Base composition: Turbine oil wt. percent 150 neutral oil (680- 850 F. boiling range) and wt. percent heavier stock (750-l,000 F. boiling range); ndM analysis-65% parafiinic, 34% naphthenic, 2% aromatic carbon atoms. Additives-0.8 wt. percent zinc dialkyl dithiophosphate and 04 wt. percent commercial rust inhibitor, oxidation inhibitor and foam suppressant.

It is evident from the above table that the compositions of this invention have excellent properties when contacted with water. The above results show that within a very short time, the oil and water phase sharply separates with minimal retention of water in the oil phase.

I claim:

1. A lubricating oil composition useful as a hydraulic fluid or turbine oil which consists essentially of an oil of lubricating viscosity having less than about 30 percent aromatic carbon atoms, from 0.1 to 2 weight percent of a zinc 0,0-dihydrocarbyl phosphorodithioate salt as an antiwear and antioxidant additive, and from 0.01 to 0.2 weight percent of a demulsifying composition having from 1 to 5 parts of an alkanol or alkanediol of from 5 to 12 carbon atoms per part of a Group II metal salt of atomic number of at least 30 of an oil soluble alkylated aromatic sulfonate.

2. A composition according to claim 1, wherein said demulsifying composition has from 2 to 4 parts of said alkanol or alkanediol per part of Group II metal sulfonate and said Group II metal is zinc.

3. A composition according to claim 1, wherein said demulsifying composition has from 2 to 4 parts of said alkanol or alkanediol per part of Group II metal snlfonate and said Group II metal is barium.

4. A composition according to claim 1 wherein said demulsifying composition is present in from 0.03 to about 0.01 weight percent.

5. A composition according to claim 1 wherein said alkanol is 4-methyl-2-pentanol.

6. A composition according to claim 1, wherein said alkanediol is hexylglycol.

7. A composition according to claim 1, wherein said zinc 0,0-dihydrocarbyl phosphorodithioate salt is zinc 0,0-dialkyl phosphorodithioate, wherein said alkyl groups are of from 4 to 12 carbon atoms.

References Cited UNITED STATES PATENTS 3,222,284 12/1965 Cook 25232.7 3,278,442 10/1966 Beerbower et a1. 252

DANIEL E. WYMAN, Primary Examiner C. G. GRAY, Assistant Examiner US. Cl. X.R. 25 275 

